– Bernd Debusmann is a Reuters columnist. The opinions expressed are his own. –

Last year, around 2,500 Mexicans died in the twin wars drug cartels are waging against each other and against the Mexican state, using weapons smuggled in from the United States. In the first 11 months of this year, the death toll was 5,367, according to the Mexican attorney general. Next year?

There is no end in sight. At least two of the lethal ingredients in the toxic brew that fuels Mexico’s ever-widening violence are unlikely to change: lax American gun laws and a Mexican border that barely controls north-south traffic. On many of the crossing points along the 2,000-mile frontier, travelers coming in from the United States, by car or on foot, are routinely waved through without even having to show identity papers.

Weak Mexican border controls rarely feature in official or academic reports on a problem that has prompted some experts and U.S. publications to wonder whether Mexico is a “failing state”. That’s the headline over a cover story on Mexico in the latest edition of the business magazine Forbes. Mexican officials reject the label.

But privately, they concede that Mexican authorities are doing a less-than-thorough job in searching and monitoring north-south traffic. They tend to point in the other direction, to the easy availability of guns in the United States, the armory of Mexico’s criminal mafias.

According to statistics from the U.S. Bureau of Alcohol, Tobacco and Firearms (ATF), the agency charged with regulating the firearms industries, there are 9,161 licensed arms dealers in the four states bordering Mexico — California, Texas, New Mexico and Arizona. Buyers from licensed establishments need to go through a background check and the serial numbers of their purchases can be traced.

No background checks and no paperwork is necessary for weapons traded between private citizens on the “secondary” market — gun shows, over the Internet, through classified advertisements. Around 40 percent of all gun sales in the United States, where private citizens own at least 200 million guns, are on the informal market, estimates the Violence Policy Center, a Washington-based group in favor of tougher gun controls.

How many guns are smuggled across the porous border? Nobody knows, and a frequently used figure of 2,000 every day appears to be more of an urban legend than an estimate based on evidence. It would amount to 730,000 smuggled guns a year.

Whatever the number, it is enough for the U.S. State Department, on its website, to advise citizens contemplating a visit to Mexico that “recent Mexican army and police confrontations with drug cartels have taken on the characteristics of small-unit combat, with cartels employing automatic weapons and, on occasion, grenades”.

AMONG WEAPONS OF CHOICE: COP KILLERS

Almost all the weapons seized inside Mexico or left at the scene of shootouts have been traced back to the United States through eTrace, an electronic system the ATF set up to trace illicit firearms. The cartel killers’ weapons of choice: AK-47 and AR-15 assault rifles. Favorite pistols: Colt .38 Super, Glock 9 millimeter, and the FN 5-7, nicknamed “cop killer” because it can pierce a flak jacket at a range of 300 meters.

All these can be legally (and easily) acquired in the United States by citizens and legal residents without a criminal record, after a background check with the Federal Bureau of Investigations that often takes less than 15 minutes. The ease with which Americans can get arms flares into public controversy at regular intervals, usually after a gun owner with a grudge commits a massacre in a school or other public place.

Attempts to introduce more restrictions have failed regularly, and this year the Supreme Court ended decades of legal argument by ruling that the second amendment of the U.S. constitution, written 219 years ago, does guarantee an individual’s right “to keep and bear arms”.

Even Eduardo Medina Mora, the outspoken Mexican attorney general who makes no secret of his frustration with the flow of weapons from the north, seems resigned to the prospect that the United States will not change its gun laws to keep Mexico from sliding into deeper trouble.

“Although … it may seem absurd to us that a (U.S.) citizen can buy an AK-47, an AR-15, or a Barrett .50, it’s the law of the land,” he told the Spanish newspaper El Pais in November. The last item on his list is a sniper rifle that costs $8,650, weighs 30 pounds and can punch through an armored vehicle from a mile away.

On the U.S. side of the border, the ATF has just launched an advertising campaign in Arizona to remind citizens that buying guns on behalf of others — so called-straw purchases — carries penalties of up to 10 years in jail. Using straw buyers has been one of the cartels’ methods to evade background checks. Gun shows are another.

Just before entering Mexico, large signs at crossing points read: “Warning: Firearms and Ammunition Illegal in Mexico.” Chances that you are stopped and searched by Mexican officials are slim.

Reuters correspondent Tim Gaynor, author of a forthcoming book on the frontier (Midnight on the Line: The Secret Life of the U.S.-Mexico Border) reports: “In scores of crossings I have made to Mexico over several years, I have been stopped on just two or three occasions. Never once have I had my car searched. The odds are heavily in favor of the smugglers.”

Time for Mexico to start watching its border rather than pointing a finger at the United States?

You can contact the author at Debusmann@reuters.com. For previous columns by Bernd Debusmann, click here.